Who makes the best al pastor tacos in town? A pork lover sets out to find the answer and stumbles across some heavy competition.

You can’t overdose on pork. I tried. Eating 18 al pastor (spit-roasted pork) tacos over three days to find the best in Chicago, my swine-laden body slowed, but it never stopped.

Al pastor (which means “shepherd style” in Spanish) evolved from lamb shawarma brought to Mexico by a wave of Lebanese immigrants during the late 19th century. Mexico’s ubiquitous street food—its answer to the Grecian gyro—is created by constructing an upside-down tapered cone, called a trompo (“top”), made up of thin slices of pork shoulder rubbed with the spice achiote and a marinade of toasted dried chiles, vinegar and Mexican oregano. Occasionally garlic, orange juice, Coca-Cola and pineapple juice are thrown in for variety.

The cone rotates over gas heat or a charcoal flame, until the outside of the pork develops a smoky char, and the orange-hued interior glistens with its own juices. My quest for the best in town took me to every end of the city. I stuck to simple taquerías—grunginess welcome but not required—and eschewed gringo mills and upscale sit-down places. I don’t advocate nibbling—I gave up trying to fit into little black dresses when my drag career ended after Halloween 1987—so if the taco was good, I downed it all and it got mentioned below. If it was bad, the remainder of the tasteless carcass was wadded up in greasy-paper-bag anonymity on the floor of my car and was omitted from the list. Before getting to the results, I’ll share the list of pastor postulates my quest gave birth to: 1) Pastor is better on weekends. Low traffic during the week usually means the meat’s not nearly as fresh. 2) A great-looking spit doesn’t mean anything. There were plenty of beautiful orange cones that beckoned me, but the meat was poorly seasoned. 3) Grilling, as opposed to spit roasting, is another method employed to cook the marinated pork. But technically, if the meat is grilled it’s called adobado and not al pastor. 4) The single biggest differentiator of al pastor tacos is its vinegar/citrus tang, the necessary balancing point to the chile spice and the herby oregano.

The best Taquería Uptown 1144 W Bryn Mawr Ave, 773-878-4785The undercounter shelves are stocked with what looks like a year’s supply of soda from Costco, the jukebox rocks Gloria Estefan and the windows are covered in cheesy adobe-colored, arched wooden vignettes. Served up in a red plastic basket, the freshly griddled corn masa tortilla held succulent and crispy char-flecked pork, with a vinegar tang that melded both sweet and hot spice.

Runner-up Carnicería Leon 1402 N Ashland Ave, 773-772-9804The thick iron window bars and the rickety signage manage to channel both a bodega and a maximum-security prison. In the back you’ll find the best-looking pork spit in Chicago manned by mustached men flicking chunks of porky goodness with serrated machetes. The only thing that stops this from being the best is its greasiness.

The rest Taquería Puebla 3619 W North Ave, 773-772-8435In Puebla, a variation of pastor known as tacos arabes is served in a thick flour tortilla called pan arabe—a cross between a tortilla and pita bread. Puebla serves decent pastor, but the smokier and spicier arabe is the choice here.

Manolos Maxwell Street Market, Sundays at Roosevelt and Canal Sts At this stalwart taco stand on the southern arm of the market, a veteran cook from the Manolo family pats fresh corn masa balls and grills them to order on a charcoal-fired kettle, creating the best tortilla base of the bunch.